<template>
  <div class="s-canvas pointer" @click="refreshCode" :style="'height:'+contentHeight+'px'">
    <canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
  </div>
</template>
<script>
  export default {
    name: "SIdentify",
    props: {
        fontSizeMin: {
            type: Number,
            default: 18
        },
        fontSizeMax: {
            type: Number,
            default: 40
        },
        backgroundColorMin: {
            type: Number,
            default: 180
        },
        backgroundColorMax: {
            type: Number,
            default: 240
        },
        colorMin: {
            type: Number,
            default: 50
        },
        colorMax: {
            type: Number,
            default: 160
        },
        lineColorMin: {
            type: Number,
            default: 40
        },
        lineColorMax: {
            type: Number,
            default: 180
        },
        dotColorMin: {
            type: Number,
            default: 0
        },
        dotColorMax: {
            type: Number,
            default: 255
        },
        contentWidth: {
            type: Number,
            default: 111
        },
        contentHeight: {
            type: Number,
            default: 40
        }
    },
    data() {
        return {
            identifyCodes: ["0", "1", "2", "3", "4","5","6","7","8","9"],
            identifyCode:""
        };
    },
    methods: {
        // 生成一个随机数
        refreshCode() {
            this.identifyCode = "";
            this.makeCode(4);
        },
        // 随机生成验证码字符串
        makeCode(len) {
            for (let i = 0; i < len; i++) {
                this.identifyCode += this.identifyCodes[this.randomNum(0, this.identifyCodes.length - 1)];
            }
            this.drawPic()
        },
        // 生成一个随机数
        randomNum(min, max) {
            return Math.floor(Math.random() * (max - min) + min);
        },
        // 生成一个随机的颜色
        randomColor(min, max) {
            let r = this.randomNum(min, max);
            let g = this.randomNum(min, max);
            let b = this.randomNum(min, max);
            return "rgb(" + r + "," + g + "," + b + ")";
        },
        drawPic() {
            let canvas = document.getElementById("s-canvas");
            let ctx = canvas.getContext("2d");
            ctx.textBaseline = "bottom";
            // 绘制背景
            ctx.fillStyle = this.randomColor(this.backgroundColorMin, this.backgroundColorMax);
            ctx.fillRect(0, 0, this.contentWidth, this.contentHeight);
            // 绘制文字
            for (let i = 0; i < this.identifyCode.length; i++) {
                this.drawText(ctx, this.identifyCode[i], i);
            }
            // this.drawLine(ctx) // 绘制干扰线
            // this.drawDot(ctx) // 绘制干扰点
        },
        // 绘制文本
        drawText(ctx, txt, i) {
            ctx.fillStyle = this.randomColor(this.colorMin, this.colorMax);
            ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + "px SimHei";
            let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1));
            let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5);
            var deg = this.randomNum(-30, 30); // 字符旋转角度(不超过45度比较好)
            // 修改坐标原点和旋转角度
            ctx.translate(x, y);
            ctx.rotate((deg * Math.PI) / 180);
            ctx.fillText(txt, 0, 0);
            // 恢复坐标原点和旋转角度
            ctx.rotate((-deg * Math.PI) / 180);
            ctx.translate(-x, -y);
        },
        drawLine(ctx) {
            // 绘制干扰线
            for (let i = 0; i < 8; i++) {
                ctx.strokeStyle = this.randomColor(this.lineColorMin, this.lineColorMax);
                ctx.beginPath();
                ctx.moveTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight));
                ctx.lineTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight));
                ctx.stroke();
            }
        },
        drawDot(ctx) {
            // 绘制干扰点
            for (let i = 0; i < 100; i++) {
                ctx.fillStyle = this.randomColor(0, 255);
                ctx.beginPath();
                ctx.arc(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI);
                ctx.fill();
            }
        },
        getCode(){
            return this.identifyCode
        }
      
    },
    mounted() {
        this.refreshCode();
    },
}
</script>